Add missing boundary check when seeking in a file.

includes/miniffs.h

@@ -101,6 +101,7 @@ typedef enum miniffs_error_t
     MINIFFS_INVALID_PARAMS,
     MINIFFS_FILE_NOT_FOUND,
     MINIFFS_ALLOCATION_ERROR,
+    MINIFFS_SEEK_OUT_OF_BOUNDARIES,
     MINIFFS_END_OF_FILE,
     //MINIFFS_,
 } miniffs_error_t;